The present invention relates to thermal printer technology, and more specifically to thermal printers using a thermal line printing head (hereinafter referred to as a "printhead") to print images on thermosensitive paper.
Compact thermal printers using thermal line printheads are well known and widely used. Occasionally, a compact thermal printer is arranged to have a thermal line printhead pressed against a rotatable platen roller. Usually, the conventional thermal printer includes, among other sensors, a paper loading detector to detect if printing paper is loaded or not loaded, and a thermal line printhead release detector which detects if the thermal line printhead is pressed against the platen roller or separated from the platen roller. The paper loading detector prohibits printing operations when paper is unavailable to the printer, and the printhead release detector prohibits or interrupts printing when the thermal line printhead is separated from the platen roller.
A conventional thermal printer, including two separately mounted detectors as described, is difficult to miniaturize and has higher manufacturing costs. Fundamentally, a single controller performs the same printing interruption instruction when either sensor is activated. However more than one sensor is conventionally necessary because of the conventional arrangement of housing portions, paper insertion and discharge slots, the platen roller, and the thermal line printhead.